Generally, when crude oil is extracted from the ground, it is commingled (e.g., co-produced) with water and natural gas. The crude oil is generally degassed and dehydrated in the oil field prior to being piped or otherwise transferred to a refinery. Preferably, water is separated from the oil via one or more separation vessels, which may include, for example, a settling tank, a free water knock-out, a heater treater, an electrostatic treater, multiples thereof, and combinations thereof, and is eventually delivered to a sales tank, which may further separate water from the oil. Separation is generally aided by, e.g., emulsion breakers, also known as demulsifiers, which assist in removing water from the oil phase. Ideally, the water that is separated and recovered from the dehydration is reasonably free of oil, and further all the oil is removed, recovered, and sold or refined.